Manganese(II) Alkyl/π-Allyl Complexes Resistant to Ligand Redistribution

Inversion Symmetry Breaking in Order-Disorder Transitions of Globular Ligands Coordinating to Cobalt(II) and Nickel(II) Bisacetylacetonato Complexes During Heating

Unexpected inversion-symmetry breaking was observed in the order-disorder phase transitions of [M(acac)₂ (abco)₂ ] (1; M=Co²⁺ , 2; Ni²⁺ , acac^- =2,4-pentanedionato, abco=1-azabicyclo-[2.2.2]-octane=quinuclidine) during heating. The isostructural, transition-free complexes [M(acac)₂ (cabco)₂ ] (3; M=Co²⁺ , 4; Ni²⁺ , cabco=3-chloro-1-azabicyclo-[2.2.2]-octane=3-chloroquinuclidine) were also studied for comparison. Complexes 1 and 2 crystallized in ordered phases in the centrosymmetric I2/m space group at 100 K, whereas they crystallized in disordered phases in the non-symmetric I2 space group at 300 K. The 60° step rotation disordering of the abco ligands was observed in the electron density maps of 1 and 2, which was consistent with the transition enthalpies estimated by differential scanning calorimetry (DSC). Gradual phase transitions were observed for 1 and 2 by DSC and powder X-ray diffraction (PXRD) at approximately 225 K. The inversion-symmetry disordering was likely induced by the local pseudo-symmetry of the abco ligands, increasing from trigonal to hexagonal and the increased steric repulsion pathways among them.

Synthesis, characterization of silicon(iv) compounds containing 2-alkyl-aminopyridine ligands and evaluation of them as CVD precursors

A family of silicon(iv) compounds, where the Si centers of trimethylsilyl (–SiMe₃) are linked with 2-alkyl-aminopyridine ligands, has been synthesized by reaction of the corresponding lithium salt of these ligands and SiMe₃Cl in a general procedure.

Synthesis, characterization, thermal properties of silicon(iv) compounds containing guanidinato ligands and their potential as CVD precursors

The title compounds of the type (Me₃Si)₂N–C(N′R)(–N′′RSiMe₃) (with R = iPr or Cy) as potential CVD precursors have been synthesized and characterized by X-ray diffraction, ¹H NMR, ¹³C NMR, ²⁹Si NMR and elemental analysis where necessary.